AMC - BETTER CALL SAUL : Los Pollos Hermanos - Taste the Family!

At the end of last season's Better Call Saul finale, [Spoiler (click to open)]Mike set out to assassinate Hector Salamanca, but his car horn goes off prompting him to abandon his mission. Returning to his car, he sees a note left on the windshield with the word "DON'T" scrawled on it. Fans speculated that this was a sign from the popular character, Gustavo "Gus" Fring, from Breaking Bad hinting to his upcoming debut on Better Call Saul. Could this promo be confirming that?
I'm ready for this. I'm also curious about that bts(?) photo posted last season of [Spoiler (click to open)]Hank (Dean Norris) and Gomie (Steven Michael Quezada) posing next to Bob's chair. Could we be seeing more classic characters in S3? Better Call Saul Season 3 is set to return Spring 2017.